package com.fly.lambda;

import org.junit.jupiter.api.Test;

public class Java8Tester
{
    @Test
    public void test()
    {
        // 类型声明
        MathOperation addition = (int a, int b) -> a + b;
        
        // 不用类型声明
        MathOperation subtraction = (a, b) -> a - b;
        
        // 大括号中的返回语句
        MathOperation multiplication = (int a, int b) -> {
            return a * b;
        };
        
        // 没有大括号及返回语句
        MathOperation division = (int a, int b) -> a / b;
        
        System.out.println("10 + 5 = " + operate(10, 5, addition));
        System.out.println("10 - 5 = " + operate(10, 5, subtraction));
        System.out.println("10 x 5 = " + operate(10, 5, multiplication));
        System.out.println("10 / 5 = " + operate(10, 5, division));
        
        // 不用括号
        GreetingService greetService1 = message -> System.out.println("Hello " + message);
        
        // 用括号
        GreetingService greetService2 = (message) -> System.out.println("Hello " + message);
        
        greetService1.sayMessage("Runoob");
        greetService2.sayMessage("Google");
    }
    
    interface MathOperation
    {
        int operation(int a, int b);
    }
    
    interface GreetingService
    {
        void sayMessage(String message);
    }
    
    private int operate(int a, int b, MathOperation mathOperation)
    {
        return mathOperation.operation(a, b);
    }
}